Axial fan

ABSTRACT

An axial fan includes an impeller. The impeller includes a hub and a plurality fan blades connected with the hub. Each fan blade includes a mounting portion provided at an inner edge thereof. The mounting portion defines a slot therein. A fastener extends through the slot of the mounting portion to fix each fan blade to the hub. An angle is defined between each fan blade and a central axis of the axial fan. The angle is capable of being regulated when each fan blade is rotated relative to the hub to cause the fastener to slide in the slot of the mounting portion.

BACKGROUND

1. Technical Field

The present disclosure relates generally to fans, and more particularly to an axial fan for dissipating heat from heat-generating components such as electronic components of computers.

2. Description of Related Art

Axial fans are commonly used in combination with heat sinks for cooling electronic components, such as CPUs of computers. Normally, the heat sink is arranged on the electronic component to absorb heat therefrom, while the axial fan is arranged on the heat sink to produce an airflow flowing through the heat sink to take the heat away.

Generally, the axial fan includes a stator and an impeller being rotatable relative to the stator. The impeller includes a hub and a plurality of fan blades extending outwardly therefrom. The stator is received in the hub. A permanent magnet is attached to an inner surface of the hub and surrounds the stator. The stator includes a stator core with coils wound therearound. When an electrical current is supplied to the coils, the fan blades are driven by the stator to rotate, thereby producing the airflow.

In selecting an axial fan for a computer, an internal structure and a heat dissipation requirement of the computer are considered in selecting the axial fan. Some computers may require an axial fan which can produce an airflow having a relatively large air volume, while some other computers may require an axial fan which can produce an airflow having a relatively large air pressure. The air volume and the air pressure are relevant to an angle defined between each of the fan blades and a central axis of the axial fan. If the angle is relatively large, a relatively large air pressure is obtained. If the angle is relatively small, a relatively large air volume is obtained.

The current axial fan generally has its fan blades integrally formed with its hub. Thus, the angle between each of the fan blades and the central axis of the axial fan is fixed and cannot be regulated or changed according to requirement. As a result, the axial fan cannot provide an air pressure and an air volume both satisfactory for all kinds of computers.

For the foregoing reasons, there is a need in the art for an axial fan which can overcome the above described shortcoming.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of an axial fan according to an exemplary embodiment of the present disclosure.

FIG. 2 is an isometric, exploded view of an impeller of the axial fan of FIG. 1.

FIG. 3 is an isometric, assembled view of the impeller of FIG. 2.

DETAILED DESCRIPTION

Reference will now be made to the drawing figures to describe the present axial fan in detail.

FIG. 1 shows an axial fan 100 according to an exemplary embodiment of the present disclosure. The axial fan 100 includes a fan frame 10, a stator (not shown) and an impeller 20 received in the fan frame 10.

The fan frame 10 defines a receiving space 19 therein for receiving the stator and the impeller 20. An air inlet 14 is formed at a top of the fan frame 10, and an air outlet 16 is formed at a bottom of the fan frame 10 opposite to the air inlet 14. The fan frame 10 includes an annular ring 11, four supporting poles 12 extending upwardly from the annular ring 11 and spaced evenly from each other along a circumferential direction of the fan frame 10, a mounting base 13 disposed at a center of the air inlet 14, and four connecting ribs 15 connecting the mounting base 13 with top ends of the supporting poles 12. The stator is received in the receiving space 19 and mounted to the mounting base 13. The impeller 20 is mounted in the receiving space 19 of the fan frame 10 and disposed around the stator.

Referring to FIGS. 2 and 3, the impeller 20 includes a hub 22, a plurality of fan blades 24 extending radially and outwardly from the hub 22, and a shaft 28 extending upwardly from the hub 22. The hub 22 includes a circular base plate 222 and a cylindrical sidewall 224 extending upwardly from an outer periphery of the base plate 222, wherein the shaft 28 extends perpendicularly and upwardly from the base plate 222 of the hub 22 towards the mounting base 13 of the fan frame 10, and the fan blades 24 extend radially and outwardly from the sidewall 224 of the hub 22. The base plate 222 is located in a center of the air outlet 16 of the fan frame 10. In the illustrated embodiment, the impeller 20 has three fan blades 24. A plurality of rods 228 is formed on an inner surface of the sidewall 224 along an extension direction of a central axis X of the axial fan 100. The rods 228 are evenly spaced from each other along a circumferential direction of the inner surface of the sidewall 224.

The three fan blades 24 are detachably mounted to the sidewall 224 of the hub 22. Three pairs of mounting holes 226 are defined through the sidewall 224 of the hub 22 for mounting the three fan blades 24 to the hub 22 via fasteners 30 such as screws. A mounting portion 25 is formed at an inner edge of each of the fan blades 24 for mounting the fan blades 24 to the hub 22. Each of the fan blades 24 is mounted to the hub 22 through the mounting portion 25. A slot 252 is defined in the mounting portion 25. The mounting portion 25 includes a pair of mounting ears 250 provided symmetrically at two opposite sides of the inner edge of each fan blade 24. The slot 252 is divided into two arc-shaped sections 252 a, 252 b. The two sections 252 a, 252 b are provided in the two mounting ears 250, respectively. The two sections 252 a, 252 b of the slot 252 of each mounting portion 25 are located on an imaginary circle and have a common center of circle. Each fastener 30 has an outer diameter substantially the same as a width of the slot 252.

In assembly, the two sections 252 a, 252 b of the slot 252 of the mounting portion 25 of each fan blade 24 are aligned with a pair of mounting holes 226 of the hub 22. The mounting ears 250 are fittingly abutted on the outer surface of the sidewall 224 of the hub 22. The fasteners 30 extend through the two sections 252 a, 252 b of the slot 252 and the mounting holes 226 of the hub 22 to fix the fan blades 24 on the hub 22. Each of the fan blades 24 is mounted to the hub 22 in an inclined manner relative to the central axis X of the axial fan 100. Particularly, each fan blade 24 is inclined from a bottom-to-top direction towards a front fan blade 24 along a rotation direction of the impeller 20. Thus, an angle θ is formed between each fan blade 24 and the central axis X of the axial fan 100.

If an air volume or an air pressure provided by the axial fan 100 is required to be regulated, the fasteners 30 are firstly loosened. The fan blades 24 are then rotated relative to the hub 22, and the fasteners 30 slide in the two sections 252 a, 252 b of the slot 252 of the mounting portions 25 of the fan blades 24. Thus, the angle θ between each fan blade 24 and the central axis X of the axial fan 100 can be easily regulated and changed according to need, and an air volume and an air pressure provided by the axial fan 100 are accordingly regulated and changed. Particularly, when the fan blades 24 are rotated clockwise relative to the hub 22, the angle θ between each fan blade 24 and the central axis X of the axial fan 100 is increased, and an enhanced air pressure is provided by the axial fan 100. When the fan blades 24 are rotated counter-clockwise relative to the hub 22, the angle θ between each fan blade 24 and the central axis X of the axial fan 100 is reduced, and an enhanced air volume is provided by the axial fan 100. As a result, the axial fan 100 can be applied to all kinds of computers.

When a permanent magnet (not shown) is mounted to the inner surface of the sidewall 224 of the hub 22, the permanent magnet is kept a distance from the inner surface of the sidewall 224 by the rods 228 provided on the inner surface of the sidewall 224, thereby avoiding an interference between the permanent magnet and the fasteners 30.

It is to be understood, however, that even though numerous characteristics and advantages of embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiment, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. An axial fan, comprising: an impeller comprising a hub and a plurality fan blades connected with the hub, each fan blade comprising a mounting portion provided at an inner edge thereof, the mounting portion defining a slot therein; and a fastener extending through the slot of the mounting portion to fix each fan blade to the hub, an angle being defined between each fan blade and a central axis of the axial fan, the angle being capable of being regulated when each fan blade is rotated relative to the hub to cause the fastener to slide in the slot of the mounting portion.
 2. The axial fan of claim 1, wherein the mounting portion comprises two mounting ears symmetrically disposed at two opposite sides of the inner edge of the fan blade, respectively, the slot being divided into two sections, and the two sections are provided in the two mounting ears, respectively.
 3. The axial fan of claim 2, wherein the two sections of the slot each are arc-shaped.
 4. The axial fan of claim 3, wherein the two sections of the slot in the mounting portion of each fan blade are located on an imaginary circle and have a common center of circle.
 5. The axial fan of claim 2, wherein the hub comprises a base plate and a sidewall extending perpendicularly from an outer periphery of the base plate, and the mounting ears are fittingly abutted on an outer surface of the sidewall of the hub.
 6. The axial fan of claim 5, wherein a plurality of rods is formed on an inner surface of the sidewall along the central axis of the axial fan.
 7. The axial fan of claim 1, wherein a mounting hole is defined through the hub corresponding to the slot, and the fastener extends through the slot and the mounting hole to fix each fan blade on the hub.
 8. The axial fan of claim 1, wherein the slot comprises at least an arc-shaped section.
 9. The axial fan of claim 1, wherein the fastener is a screw.
 10. The axial fan of claim 1, further comprising a fan frame, the fan frame comprising an annular ring, a plurality of supporting poles extending from the annular ring, a mounting base disposed above the annular ring, and a plurality of connecting ribs connecting the mounting base with free ends of the supporting poles.
 11. The axial fan of claim 10, wherein an air inlet is formed at a top of the fan frame, an air outlet is formed at a bottom of the fan frame opposite to the air inlet, and the mounting base is disposed at a center of the air inlet.
 12. The axial fan of claim 11, wherein the impeller is mounted in the fan frame and coupled to the mounting base. 